Differential gear assemblies are provided in driven axles of vehicles to permit left and right driven wheels to rotate at different speeds whilst transmitting torque; as is well known, such an arrangement is required to permit a vehicle to turn from a straight line.
Many kinds of different gear assemblies have been proposed, but the most common consist of a casing in which at least one rotatable differential side gear is arranged in mesh with opposite end gears of the vehicle drive shafts. The casing carries an annular crown wheel which is driven by a pinion of an input shaft, which itself is driven by the vehicle engine.
The aforementioned side gears are rotatably mounted on a gear shafts, which are, in turn, received within openings of the casing. In order to prevent the gear shafts from moving radially outwardly out of the casing, as a result of separating forces between the differential side gears and the end gears of the half shafts, it is commonly known to fix the gear shaft in place with respect to the casing, by fastening screws. Depending on the construction of the differential gear assembly, it is often required to fix the gear shaft in place before the crown wheel is attached to the casing, as the crown wheel may prevent any access to the gear shafts thereafter. At this point, the gear shafts must be reliably connected to the casing as a correction of the connection between the casing and the gear shafts may no longer be possible. This is particularly problematic if the crown wheel permanently attached to the casing, e.g., by welding.
In view of the above, it is an objective of the present invention to provide a gear assembly and a method of assembling the latter to provide a stable connection between the gear shaft and the casing can be achieved reliably before the crown wheel is attached.